Method and apparatus for determining the degree of cohesion in multifilament yarn strands



p 1968 c M. RICE 3,401,559 7 METHOD AND APPARATUS F OR DETERMINING THE DEGREE OF COHESION IN MULTIFILAMENT YARN STRANDS 2 Sheets-Sheet 1 Filed Oct. 28, 1965 CHARLES M. RICE L. J. WILBURN ATTORNEY INVENTOR.

Sept. 17, 1968 c. M. RICE 3,401,559

METHOD AND APPARATUS FOR DETERMINING THE DEGREE OF COHESION IN MULTIFILAMEI JT YARN STRANDS Filed Oct. 28, 1965 2 Sheets-Sheet 2 f I I 24 .mllllll ,l-

INVENTOR.

CHARLES M. RICE BY L.J. WILBURN ATTORNEY I United States Patent 0 3,401,559 METHOD AND APPARATUS FOR DETERMINING THE DEGREE 0F COHESION IN MULTIFILA- MENT YARN STRANDS Charles M. Rice, Candler, NC, assignor to American Enka Corporation, Enka, N.C., a corporation of Delaware Filed Oct. 28, 1965, Ser. No. 505,538 2 Claims. (Cl. 73-160) ABSTRACT OF THE DISCLOSURE The amount of filament entanglement or cohesion in multifilament yarn may be determined automatically by feeding a predetermined amount of yarn over a needlelike yarn probe which is mounted for movement as filament entanglement occurs, and by recording movement of the yarn probe while simultaneously releasing the probe from yarn entanglement to permit reinsertion and additional recording at another point in the continuously moving yarn.

This invention relates to a method and apparatus for determining, in a running length of textile yarn, the degree of cohesion existing between the individual filaments of the yarn.

In the production and use of multifilament yarns, it is necessary to maintain enough cohesion in the individual filaments of the yarn strand to enable the strand to be woven, tufted, or knitted into end-products. Cohesion in a multifilament yarn strand can be improved in various Ways. The yarn may be coated with an adhesive solution. Probably the best known way is by twisting the yarn strand along its length to linearly disoreient the filaments about each other. A more recent method of producing filament cohesion in a yarn strand involves subjecting a moving strand to fluid pressure, usually air, whereby the individual filaments of the strand are randomly disoriented to interlace the filaments along the yarn length.

Aside from achieving improved cohesion, yarns are often subjected to a high pressure fluid stream to mechanically disorient the filaments of a strand and produce bulky yarn. Multifilament yarns bulked in such manner produce novel effects in textile products. Carpets containing bulked yarns have a more aesthetic appearance and give greater covering power per unit area. Knitted and woven wearing apparel made from bulked yarns possess improved covering power, greater warmth, and better hand.

For better quality control of yarns which are subjected to mechanical filament disorientation, i.e., twisting, air jet interlacing, and bulking, it is necessary to be able to evaluate the yarns to determine the degree of disorientation to which the filaments have been subjected. To achieve product uniformity, it is desirable that the twist and tangle level of the yarn filaments be as similar as possible to their companion yarns.

One method used to determine the degree of interlacing of the individual filaments of a tangled yarn is known as the hook-drop method. This method, disclosed in US. Patent No. 2,985,995, requires that a large number of short length samples of yarn be cut from the yarn for evaluation. Each sample is, in turn, manually fastened to a vertical graduated scale. The lower end of the sample is weighted, the yarn bundle carefully separated with a pointed instrument, and a weighted hook inserted into the yarn and lowered at a specific rate of travel until it is supported by the yarn. The average distance traversed by the hook indicates the degree of entanglement, or coherency factor, of the yarn.

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Such a test has disadvantages. Because multiple samples must be prepared and the test manually performed on each sample, the test is quite time consuming and does not lend itself to the continuous processes of commercial production.

It is an object of the present invention to provide a process and apparatus for testing the filament coherency in a yarn strand which overcome to a great extent the disadvantages and imperfections of the prior art.

It is a primary object of the invention to provide a novel method of determining, in continuous manner, the degree of coherency of the filaments in a multifilament yarn.

A further object of the invention is to provide novel apparatus for determining the coherency in a multifilament yarn.

These and other objects of the invention will become apparent from the following detailed description of the invention and the accompanying drawings.

According to the present invention, it has been discovered that, by the use of the novel apparatus disclosed herein, it is possible to quickly determine the degree of coherency in a yarn by measuring the disorientation that exists in filaments of a textured yarn strand which has been subjected to mechanical filament disorientation, In the present invention, a traveling multifilament yarn which has been previously twisted of air-jetted to linearly disorient the filaments is passed over a needle-type sensor extending into the approximate center of the yarn strand. The needle is biased in a direction opposite to direction of travel of the yarn. When a given amount of resistance builds up in the yarn due to the filament disorientation, the needle is displaced from the yarn path to produce a signal indication. This signal is automatically recorded and the needle is returned to its position in the yarn strand for subsequent displacement.

By determining the number of needle displacements which occur in a given amount of yarn travel, a value is obtained which, when compared with the value obtained from other textured, multifilament yarns, is an indication of the relative degree of cohesion existing in the yarns.

The yarns of the present invention are drawn from a suitable supply source, such as a pirn, through a thread tensioning device which maintains a constant tension on the yarn. The yarn passes from the yarn tensioner, by means of a series of yarn guides, vertically past a needletype coherency sensor. Yarn movement past the sensor is effected by a yarn-gripping roller driven by a constant speed, synchronous motor. The motor may be operated continuously or programmed by suitable means to pass a desired amount of yarn through the system.

The device for sensing the degree of coherency of the yarn strand is composed of a needle-shaped, thin probe which is pivotally mounted and positioned so as to penetrate and extend through the approximate middle of the yarn strand as it moves in a vertical direction. The probe, which extends horizontally into the yarn strand, is biased against the direction of yarn travel by an adjustable weight attached to the probe. As twisted and tangled multifilament yarn is drawn over the probe, the amount of twist and/or entanglement existing in the yarn exerts an upward pressure on the probe. When sufiicient pressure is exerted on the probe, the yarn moves the probe upward, against its biasing weight, in the direction of yarn travel. Probe movement generates an impulse which simultaneously registers a tangle count and activates means which remove the probe from the point of resistance in the yarn and immediately reinsert the needle into the moving yarn.

By maintaining a constant tension on the traveling y-arn and controlling the amount of yarn which passes the probe, the number of tangle counts recorded is an indication of the degree of cohesion that exists in the yarn. By experimentally determining the optimum number of tangle counts which must exist in disoriented filament yarn to produce the product desired, i.e., carpet yarn, knit fabrics, woven goods, such yarns can be continuously checked for product uniformity.

Further elucidation of the invention may be accomplished by reference to the drawings and descriptions thereof.

FIGURE I is an overall presentation of the tangletesting system containing yarn to be evaluated threaded into the system for evaluation.

FIGURE II is a detailed view of the filament cohesion sensor and yarn displacement device of FIGURE I in cohesion-sensing position.

FIGURE III is a detailed view of the filament cohesion sensor and yarn displacement device of FIGURE I, showing the position of the displacement device and sensor as the sensor is separated from the yarn strand.

In FIGURE, I yarn 2 which has been tangled or twisted in a texturizing step, is fed from yarn package 1 through a constant tension device 3. Constant tension devices are well known and in the present embodiment a Kiddle Double-Disc Compensating Tensioner, model B, is used. Via yarn guides 4, 5, and 9 the yarn is directed vertically past the cohesion-sensing components of the system. These components consist of a filament cohesion sensor 7 and a yarn displacement device 6. A cohesion entanglement counter 8 is operatively connected thereto. Cohesion-sensing components 6 and '7 are shown in more detail in FIGURES II and III and their operation is explained below. The yarn is moved through the system by motor-driven (not shown) yarn roll 12, To prevent slippage of the yarn about drive roll 12, the yarn is passed several times about a yarn wrapping guide 10 and a yarngripping friction roll 11, which friction roll is biased against roll 12 to press the yarn onto the surface of the roll. From yarn drive roll 12 the yarn 2 may be passed to waste or recollected for subsequent use. The yarn dis placement device 6, filament cohesion sensor 7, and cohesion entanglement counter 8 are electrically connected by a power supply network 14 containing a normallyopen switch 13.

FIGURES II and III show, in detail, the arrangement and operation of the cohesion-sensing components of the system. The filament cohesion sensor 7 is composed of a pivot arm 15 rotatably supported by pivot support 16. An

adjustable weight 17 may be moved along arm 15 to increase or decrease the bias on needle probe 18, depending on the particular yarn being tested. As seen in FIG- URE II, needle probe 18 is centered in the traveling yarn strand 2 by yarn centering guides 19. These guides insure that the probe penetrates the approximate center of the yarn strand when the needle probe is contacted by the yarn.

The yarn displacement device is composed of a pulltype solenoid 20 having a yarn displacement arm 21 upon which are mounted yarn displacement guides 22. Upon activation of the solenoid 20, the yarn displacement arm 21 moves in horizontal direction to the right, displacing the yarn path and removing the yarn strand from needle probe 13 and yarn centering guides 1? (see FIGURE III). Upon deactivation of the solenoid 20, spring 23 returns the yarn displacement arm horizontally to the left.

The operation of the cohesion-sensing components is as follows. As the yarn bundle 2 travels upwardly past needle probe 18, the twist and/or entanglement in the filaments of yarn strand 2 exerts pressure on the probe. When yarn which has been twisted is tested, the needle probe 18 strips the twist back for a distance along the running yarn. \Vhen the pressure exerted by the yarn overcomes the force of adjustable weight 17, the filament cohesion sensor 6 rises to close normally-open electrical contacts 25 and 26 (FIGURE III) and activate power supply network 14. Activation of power supply network 14 simultaneously energizes the pull-type solenoid 20 of yarn displacement device 6 and records a tangle count on the cohesion entanglement counter 8. Yarn displacement arm 21 is drawn by solenoid 20 to the right and yarn displacement guides 22 withdraw the yarn bundle from the needle probe 18. The force of weight 17 rotates pivot arm 15 and moves needle probe 18 away from electrical contacts 25 and 26 which separate todeactivate power supply network 14. Deactivation of power supply network 14 releases the electric impulse on the solenoid 20. Spring 23 then moves yarn displacement arm 21 to the left so that the yarn strand 2 again contacts needle probe 18. Yarn centering guides 19 insure that the needle probe 18 penetrates the approximate center of the yarn bundle. Passage of the yarn past the needle probe 18 again builds up pressure and the foregoing cycle is repeated.

The number of tangle counts recorded by the cohesion entanglement counter S in a given amount of yarn travel is an indication of the degree of cohesion existing in the filaments in the yarn.

From the foregoing detailed description of the invention, it can be seen that the relative cohesion of various yarn samples can be determined. The tension on device 3 and the force exerted by the weight 17 can be adjusted to compensate for varying yarn deniers and filament counts. With knowledge of the number of tangle counts existing in various end product yarns, the quality of the yarn products can be closely controlled.

In order to compare two yarn samples, it is obvious that the same length of yarn must pass the filament cohesion sensor for each sample. To insure this, yarn drive roll 12 is controlled to pass a given amount of yarn during each test. Various means may be used to control the amount of yarn take ofi, such as timing means or cams, and such control means are considered obvious to those skilled in the art.

While specific apparatus embodying the present invention has been described above, it will be apparent that many changes and modifications may be made therein without departing from the spirit of the invention, For example, the yarn may move in a stationary linear path and the filament cohesion sensor be displaced therefrom. It is also unnecessary that the yarn be passed vertically to take advantage of gravity forces to return the filament cohesion sensor to the yarn. The yarn may be passed horizontally, with suitable means to remove and replace the needle probe from the yarnpath as cohesion counts are made It will therefore be understood that the particular apparatus and procedure set forth above are intended to be illustrative only, and are not intended to limit the invention. I

What is claimed is:

1. A method of determining the degree of cohesion in filaments of a multifilament yarn which has been subjected to a mechanical treating step whereby the filaments in the yarn are linearly disoriented to improve their 00- hesion, comprising the steps of (l) continuously passing a yarn strand under constant tension and at controlled speed past a filament disorientation sensing point;

(2) sensing a number of filament disorientation points in the moving yarn; and

(3) recording the number of sensed points occurring in a given amount of yarn passage to determine the degree of cohesion existing in the yarn.

2. Apparatus for recording the amount of filament cohesion in a length of multifilament yarn comprising (a) feed means for continuously moving a predetermined amount of multifilament yarn at a constant speed along a linear path; 7 I

(b) means for maintaining a constant tension on the moving yarn;

(c) a yarn probe mounted for limited movement from a first to a second position alongside the linear yarn path;

((1) biasing means normally urging said yarn probe and said multifilament yarn into engagement with the probe inserted into the filaments of the yarn, whereupon filament cohesion in the moving yarn will cause movement of the yarn probe from said first to said second position;

(e) bi-functional means responsive to movement of the yarn probe to said second position for recording the filament cohesion and for concurrently disengaging the yarn probe from the yarn; and

(f) means for returning the yarn probe to said first position thereof and for simultaneously deactivating the bi-functional means to permit reinsertion of the yarn probe through operation of the biasing means at a subsequent point in the continuously moving yarn.

References Cited UNITED STATES PATENTS 3,290,932 12/1966 Hitt 73160 DAVID SCHONBERG, Primary Examiner.

J. NOLTON, Assistant Examiner. 

